1. Field of the Invention
The present invention relates to a lubricating oil guiding system for motor bearings. In particular, the present invention relates to a lubricating oil guiding system using a separating plate placed between two adjacent bearings through which a rotor shaft of a motor extends, thereby achieving even distribution of lubricating oil and thereby improving the lubricating effect and the circulating effect of the lubricating oil.
2. Description of Related Art
FIG. 1 of the drawings illustrates a conventional motor comprising a base 10, a stator 20, and a rotor 30. An axial tube 11 is mounted to the base 10, and an oily bearing (or sleeve bearing) 12 is mounted in the axial tube 11. A substantially U-shaped supporting plate 13 is mounted in a bottom end of the axial tube 11 for supporting a distal end of a shaft 31 of the rotor 30 and defines an oil reservoir 131 for receiving lubricating oil. The shaft 31 extends through an axial hole 120 of the oily bearing 12. When the shaft 31 turns, the lubricating oil in the oil reservoir 131 circulates through an inner periphery delimiting the axial hole 120 of the oily bearing 12, a top face of the oily bearing 12, a chamber 121 on the top face of the oily bearing 12, a gap between the oily bearing 12 and the axial tube 11, and a bottom face of the oily bearing 12.
Although the oily bearing 12 may reduce wear to the elements of the motor, the lubricating oil requires supply from the oil reservoir 131 in most cases. Further, since the upper part of the oily bearing 12 is far away from the oil reservoir 131, lubrication of the upper part of the oily bearing 12 can be achieved only when the shaft 31 turns. However, the lubricating effect in the upper part of the oily bearing 12 is unsatisfactory if the oily bearing 12 has a relatively long axial length or loss of lubricating oil occurs. Thus, the friction in the upper part of the oily bearing 12 increases, leading to reduction in the rotating speed of the rotor 30 and generation of noise and heat. Even worse, the shaft 31 would get stuck and thus shorten the life of the motor.
Another conventional motor is disclosed in, e.g., U.S. Pat. Nos. 6,336,745 and 6,435,722. The motor of this type comprises a base, a stator, a rotor, an axial tube, and an oily bearing. The rotor includes a shaft having an annular groove that faces an intermediate portion of the oily bearing. The annular groove assists in storage and circulation of the lubricating oil. Thus, when the shaft turns, the upper part of the oily bearing can be quickly lubricated by the lubricating oil stored in the annular groove. However, after a period of operation, the annular groove may receive excessive lubricating oil, resulting in excessive oil pressure and thus adversely affecting rotational balance of the rotor. Further, the outer lubricating oil path outside the oily bearing is still too long and thus not allows rapid circulation of the lubricating oil.
U.S. Pat. No. 5,941,646 discloses a hydrodynamic type porous oil-impregnated bearing and a bearing device. U.S. Pat. No. 5,762,423 discloses a bearing device, a solid resin lubricating composition, and a porous oil-impregnated bearing. U.S. Pat. No. 6,338,575 discloses self-lubricating bearings and assemblies thereof. According to teachings of these patents, several oil-impregnated bearings can be mounted in an axial tube of a motor to increase the number of circulating lubricating systems. This shortens the lubricating oil path and thus improves the lubricating oil circulating efficiency of the oil-impregnated bearings. However, the outer paths and the inner paths of all of the circulating lubricating systems are communicated and thus interfere with one another, failing to reach the anticipated lubricating oil circulating effect.
A further conventional motor is disclosed in, e.g., Taiwan Utility Model Publication No. 576482. The motor of this type includes an axial tube having an oil reservoir in a bottom thereof An oily bearing is mounted in the axial tube. An oil inlet is defined in a bottom end of the oil reservoir and aligned with a plurality of lubricating oil grooves defined in an outer periphery of the oily bearing. Each lubricating oil groove includes a through-hole in a bottom wall thereof, with the through-hole being communicated with an oil storage chamber in an axial hole of the oily bearing. The lubricating oil are guided by the lubricating oil grooves and the through-holes back to the oil storage chamber, providing sufficient lubrication to an inner periphery delimiting the axial hole of the oily bearing and the shaft of the rotor. However, formation of the through-holes and the oil storage chamber is difficult. Further, lubrication of the upper part of the oily bearing is not unsatisfactory, as no lubricating oil grooves are defined in the upper part of the oil bearing.